Heat-resisting alloy steel and articles made therefrom



Patented Nov. 3, 1925.

UNITED STATES,

PATENT OFFICE.

enoaen a; men, or BATTLE GREEK, men ream fiEAT-RESISTING ALLOY STEEL AND ARTICLES'M ADE THEREFROM. I

p 30 Drawing.

as for instance when used forpoppet valves for internal combustion engines.

The principal object of this invention is to produce an alloy steel in which the conversion is relatively high, and in which the characteristics of the steel obtained from all of the heats will remain substantially constant, whereby the same or substantially the same heat treatment may be used in the production of articles made from the alloy.

Many attempts have been made hercto fore, to produce an alloy steel suitable for the production of poppet valves, with partial success, but when an attempt has been made Y to produce a relatively inexpensive alloy steel which will resist hot oxidation, it has been found in the actual manufacture of valves from such steel, that it is wild that is to say, no two heats are alike and consequently one lot of steel requires heat treatment different from another lot and as a result much time, labor and loss of material is experienced in the actual manufacture-of valves from such steel. ,Moreover the conversion is low, sometimes as low.

4 as percent, which as a matter of fact, increases the cost of production of the steel and articles made therefrom.

In accordance with the present invention, alloy steel, containing the materials in and about the proportions specified, runs substantially constant, each heat being practically like the preceding ones; the conversion is relatively hi h, consequently, while more suitable and esirable materials are used, the cost of production is not .so great because the loss 1n conversion 1s less. The

heads of valves when forged or shaped up by the hammering process will be found to have a smooth, unbroken surface, free from in Heat-Resisting Application filed April 27, 1925. Serial nofzazse.

scale, and requiring no machining. This is a great savlng 1n the cost of production, and by reason of this characteristic of the surface, the valve effectively resists hot oxidation.

Theprincipal alloying elements in'the present steel are chromium and nickel; some manganese andsilicon are used, and a small quantityof phosphorusand sulphur is present as usual, the remainder is principally 1ron. The carbon content is relatively low.

The proportions may vary slightly within the l1m1tsg1yen, and a less eflicient alloy may be obtained if some of the materials exceed the specified limits. For obtaining The remainder iron.

' Valves made from alloy steel containing the materials in the proportions specified in the above schedules are tough and hard and" the surface will standwear and resist hot oxidation. The danger of surface decarbonization, 1f left in the fire too long, is reduced to a m1n1murn-that is, one of the drawbacks of medium priced alloy steels now on the market for use in the manufacture of valves. The steel is readily workable at temperatures ranging from 1600 to 1800 de grees Fahrenheit, and may be air cooled or quenched in water. The steel is not wild but its characteristics remain substantially constant. For this reason the mills are able to produce amedium priced alloy steel which does contain the non-corroding, non-oxidizing characteristics attributed to many of the so called'alloys having high resistance to hot oxidation.

'1 claim as new and desire to secure by Letters Patent:

1. alloy steel having high resistance to hot oxldation, having a composition substantially as follows: chromium 7.00 to the best results, the following proportions have been used'successfully in the manufacture of poppet valves in great numbers I Per cent.

Chromium 7.00 to 8.00 N ckel 1.25 to 2.25 Phosphorus and sulphur under .03 Manganesenfl .45 to .65 Silicon .50 to 1.00 Carbon .35 to .45

8.00% nickel 1.25 to 2.25% phosphorus and Sulphur together, under .03%; manganese 8.00% nickel 1.25 to 2.25%; phosphorus and .45 to .65%; silicon .50 to 1.00%; carbon .35 sulphur together, under 03%; manganese .45 to 45% and the principal part of the reto .65%; silicon .50 to 1.00%; carbon .35 to 10 mainder iron. .45% and the principal part of the remain- 5 2. Forged metal articles having high re 'de-r iron. I

sistance to hot oxidation'and composed of alloy steel containing chromium 7.00 to GEORGE R. RICH. 

